There are previously known safety interlocking systems for protecting electrical equipment users and technicians against hazards, such as electrical shock, burns, radiation, and improper operating modes.
For example, it is well known to enclose a hazardous apparatus in a protective cage having an access door or panel, the removal of which actuates a safety interlock switch. Such a safety interlock switch typically removes primary power from the electrical equipment and must, therefore, be rated to carry primary currents and voltages.
In another example, some electrical equipment include a module that is removable for servicing or replacement. Often the removable module is secured behind or attached to an access panel. Typically, such removable modules are secured within the electrical equipment by mechanical fasteners and have separate electrical interconnections, safety interlock switches, and related wiring harnesses.
Portable image projectors present an interesting mix of requirements and hazards. Many such projectors employ a metal-halide arc lamp that operates at a very high temperature, requires a high voltage pulse to ignite the arc, must be readily replaceable, must be compact and lightweight, and must be packaged to protect users and the projector from heat, high voltage, and improper operating modes, such as operation of equipment at excessive temperatures, and high-voltage pulse generation during arc lamp replacement.
Portable image projectors are generally referred to as being "ultra-portable" if they are small enough and light enough to be carried by one hand. However, the above-described arc lamp hazards and requirements generally contribute to making the arc lamp-related apparatus among the bulkiest and heaviest of those used in portable image projectors, rendering them undesirable for use in ultra-portable projectors.
What is needed, therefore, is a compact, lightweight, and safe arc lamp apparatus that is suitable for use in portable and ultra-portable image projectors.